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That search engine optimization (
) no longer consists of just listing the right keywords should be obvious. The Page Experience, aka user experience of a Web site, plays an increasingly important role for ranking in search results. This is also evidenced by the upcoming Page Experience Update From Google in which the Core Web Vitals be an important factor. This upcoming update will be rolled out gradually starting in June as a new ranking factor and will be fully live by the end of August.

Much has been said and written about this impactful update. But, what exactly does Core Web Vitals entail? How does Google measure these factors and how important is it for your website to have the Core Web Vitals in order? You’ll read about it in this article.

What are Core Web Vitals?

The Core Web Vitals are a part of the User Experience. Specifically, the Core Web Vitals are three metrics that Google uses to measure the User Experience of a Web page. These metrics consist of:

  1. Largest Contentful Paint (LCP)
  2. First Input Delay (FID).
  3. Cumulative Layout Shift (CLS)

Largest Contentful Paint (LCP)

This first metric measures the loading speed of the Web page. The loading time of a Web page is an important factor in user experience. After all, no one wants to wait a long time when opening a web page. Google measures this by looking at how long it takes for all content to load. A load time under 2.5 seconds is considered a good score in this regard. Does it take longer than 4 seconds to load? Then the LCP is rated as poor. A load time between 2.5 and 4 seconds is rated by Google as moderate.

Afbeelding waarin de drie beoordelingen van Google over de LCP worden weergegeven

First Input Delay (FID).

The First Input Delay (FID) measures the interactivity between the visitor and the Web page. This is measured by Google as the time between loading the page and when the visitor can first interact. This includes actions such as being able to click buttons and fill out forms. A good score on the FID is less than 100 milliseconds. A score above 300 milliseconds is considered poor. A score between 100 and 300 milliseconds is rated by Google as mediocre.

Afbeelding waarin de drie beoordeling omtrent de CLS worden weergegeven

Cumulative Layout Shift (CLS)

The Cumulative Layout Shift (CLS) includes the visual stability of a Web page. For this metric, it is important that elements on a page do not move while loading. The CLS of a Web page is measured by looking at the impact fraction and the distance fraction within the viewport. A viewport is also known as the visible portion of a Web page. Thus, if a Web page is longer or wider than the viewport, users will have to scroll to view the entire page.

The impact fraction is the percentage of the viewport occupied by the shift. The distance fraction is the percentage of the distance within the viewport that the shifting fraction has traveled. This is calculated as Impact fraction times the distance fraction. An example:

An element that shifts takes up 20% of the viewport and then shifts down 20%. The impact friction in this case is 40%, aka 0.4. In this case, the percentage that the shifting part has traveled within the viewport (distance fraction) is 20% and thus 0.20. The CLS is then calculated as: 0.4 x 0.20 = 0.08. A good score on CLS is 0.1 or lower at 75% of page visits. A score higher than 0.25 is rated as poor. A score between 0.1 and 0.25 rates Google as moderate.

Afbeelding waarin de drie beoordeling omtrent de FID worden weergegeven

Why are Core Web Vitals important to Google?

A good user experience of a website is important to Google. Of course, when you are looking for something, you want to find it as quickly as possible. Therefore, it is important to Google that you get an answer to your search quickly, and so user experience plays a big role. Moreover, a higher user experience also contributes to a higher conversion rate. In contrast, a low user experience, on the other hand, negatively impacts a website’s ranking and conversions.

Why Core Web Vitals are important for all online marketing

Having the metrics in place for the Core Web Vitals go beyond SEO. User friendliness and thus Core Web Vitals is also important for SEA, conversion optimization and content marketing. A worse score on the Core Web Vitals lower a landing page’s quality score, which is unfavorable for SEA. This lowers the effectiveness of paid search campaigns, potentially resulting in higher costs.

When the Core Web Vitals are in order, it can help with mapping the relationship between user experience and conversion rate. Where necessary, the user experience can be improved, which positively affects conversion optimization. The same is true in the area of content marketing. The Core Web Vitals help communicate the relationship between user experience and content quality. Possible deficiencies in engagement (user engagement) can be improved in this way.

These are the other important criteria for a good Page Experience according to Google

In addition to the Core Web Vitals, there are currently already a number of other criteria by which Google judges the user experience of a Web page. These points, along with the Core Web Vitals, belong to the Page Experience Signals and consist of:

  1. Mobile Friendly
  2. Safe Browsing
  3. HTTPS
  4. Non-Intrusive Interstitials

Mobile Friendly

Mobile Friendly, also known as the mobile user experience, plays an important role in the field of user experience. More than three-quarters of all page visits come from mobile traffic. Therefore, it is more than logical that Google includes the mobile user experience as an important factor in its Page Experience rating. In addition, more and more web developers are choosing a Progressive Web App.

Safe Browsing

Safe Browsing has been included by Google since 2007 when it comes to the Page Experience. This mainly involves security and combating phishing attacks, malware and other unwanted viruses. In the case of a website where potential risks are detected, user access is blocked.


HTTPS is a standard website security protocol that encrypts information between the sender and receiver. So in this way, unwanted third parties can do no harm. Moreover, HTTPS not only protects visitors’ data, such as entered data, but also ensures that no connection can be made to a wrong address. HTTPS provides three layers of protection: encryption, data integrity and authentication. Security is an important part of the Page Experience, and it stands to reason that HTTPS is part of it.

Non-Intrusive Interstitials

Non-Intrusive Interstitials are also known as intrusive ads. So here you can think of annoying pop-ups. Google agrees that unsolicited and intrusive pop-ups are annoying, which is why they include the presence of such ads in their Page Experience ratings. Things like indicating legal obligations or warnings, a login window or a small banner are not considered intrusive interstitials by Google.

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